Method and device for supporting lightly loaded structures and pavements on highly expansive soils

Abstract

A device and method for supporting lightly loaded structures on highly expansive soils. A plurality of domes is positioned between the lightly loaded structure and the soil. Each of the domes has a convex side and a concave side. The convex side faces upward against the lightly loaded structure and the concave side faces downward against the soil. The concave side provides a void area for expansion of soil. Each dome also has two soil contact ends. The soil contact ends provide a small contact area with the soil to increase the pressure exerted by the lightly loaded structure at the soil contact area to overcome the swelling effects of expanding soil. In a preferred embodiment each dome is fabricated from PVC pipe.

Description

[0001]The present invention relates to the support of structures in soil, and in particular to supporting lightly loaded structures on highly expansive soil.BACKGROUND OF THE INVENTION[0002]Expansive soils (also known as swelling soils or active soils) cause foundation and pavement problems worldwide. Expansive soils are found abundantly in both developed and underdeveloped countries. They are abundant in California, Colorado and Texas. Worldwide, they are found in Oman, South Africa, Palestine, Mexico, China and many other nations. They are a particular problem for lightly loaded structures such as one story houses, pavements, warehouses and airport runways. In the United States, expansive soils cause more loss than fire, flood and earthquake damages combined, each year.[0003]Expansive soils are currently identified by Expansion Index Test, Percent Swell Test, Swelling Consolidation Pressure Test or Potential Vertical Rise Analysis. Clays and Claystone materials that contain Montmo...

AI Technical Summary

Benefits of technology

[0014]The present invention provides a device and method for supporting lightly loaded structures on highly expansive soils. A plurality of domes is positioned between the lightly loaded structure and the soil. Each of the domes has a convex side and a concave side. The convex side faces upward against the lightly loaded structure and the concave side faces downward against the soil. The concave side provides a void area for expansion of soil. Each dome also has two soil contact ends. The soil contact ends provide a small contact area with the soil so as to increase the pressure exerted by the lightly loaded structure. This overcomes the swelling effects of expanding soil. In a preferred embodiment, the dome is a split PVC pipe (Schedule 40) that is placed with its opening towards the soil. These domes are preferably placed next to each other with a maximum separation of 0.33 inches between them.

Problems solved by technology

This is time consuming and expensive.

Also suitable soils for replacement may not be readily or locally available.

This is not feasible in developing countries and is not cost effective in small size projects.

This is only successful in moderately swelling soils.

In addition, it is expensive method due to the required amount of concrete, steel rebar and added labor cost.

This method had only limited success in soils of low to moderately expansive soils and had no success in soils of high swelling pressures.

This embodiment does not significantly reduce the contact area of the concrete slab and had no success in soils with moderate to high swelling pressure.

This method is the most expensive method and due to technological aspects, it is only available to residents of developed nations.

As can be seen, the problems caused by swelling soils are understood but the available solutions are expensive and cause the home construction cost to increase substantially in developed nations.

In developing countries, they make it hard for a poor family to own a distress free home for any extended period of time.

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